Integrated circuit technology involves integrating many elements into one semiconductor device. With increased complexity in semiconductor devices, various testing methods have been proposed.
External stand-alone machine type test devices are common. However, memory, such as that in a microprocessor memory device or an embedded memory device, which has no pad or similar means of access, may not be tested using stand-alone machine type testing devices.
Therefore, putting a built-in self-test circuit (BIST) into the semiconductor device has been proposed. However, in the conventional built-in self-test circuit (BIST) a test for all commands may not be performed making the test coverage is low.
Each of the tests verifies normal memory device operation in different ways leaving possibly different results between the various testing methods. Therefore, testing methods are not perfect and may fail to accurately analyze the functionality of a given semiconductor device.